By Mary Ann Lila, PhD Director, Plants for Human Health Institute North Carolina State University
Plants, and most especially, plants growing in harsh, exposed environments out in the wild, produce a bounty of powerful health-protective natural chemical compounds which can provide broad spectrum health benefits against cancer and other chronic human diseases.
Why do plants manufacture compounds (phytochemicals) that uniquely protect against chronic human diseases?
Plants are clearly not producing powerful phytochemicals for the sole purpose of benefitting humans. Plants have no other means to protect themselves except to creatively synthesize and accumulate a sophisticated assortment of natural components in their organs (such as leaves, roots or fruits). This internal phytochemical cocktail helps the otherwise unprotected plants to endure environmental stress and promote their own survival, or at least improve their chances of passing on their seeds to grow the next year. Phytochemicals offer remarkably sophisticated natural defenses that can help plants to thrive in even hostile locations.
How do these phytochemicals work?
For example, the flavonoid set of phytochemicals includes the bright red and blue pigments, and the astringent tannins found in many fruits, flowers and vegetables. These flavonoids can discourage a predatory insect from feeding off of the plant’s leaves, or can act as natural fungicides or bactericides to discourage attack by invading microbes. These same flavonoids can help screen delicate plant tissues from exposure to harsh sunlight or help toughen its tissues to ward off cold temperature or salt stress. Because of the bright colors in some of these compounds, the flavonoids can help attract insects or birds to help pollinate flowers or eat fruit, and therefore help the seeds to be dispersed widely, which will help the plant’s next generations to survive.
What happens when humans eat these flavonoid-containing plants, like berries?
The phytochemicals naturally moderate the body’s reaction to diseases, stress and allergens. These same phytochemicals interact with target sites in the body to protect against foreign invaders like bacterial cells, damaging rogue enzymes, or free-radical damage. Flavonoids protect the body’s cells from the damaging effects of reactive oxygen species, such as those from ultraviolet sunlight rays or pollution exposure. By inducing antioxidant enzymes in your body, the flavonoids help your body to cope with toxins.
Flavonoids are well known for their anti-inflammatory effects, which provide natural therapy for cardiovascular diseases, ulcers, many types of cancers and allergies. Once eaten and digested, plant flavonoids protect the inner lining of human blood vessels, aiding blood flow, and also confer many positive benefits by modulating blood sugar levels and lipid metabolism.
Why can a wild plant provide the most potent phytochemical protection against human disease?
Plants in the wild are at the mercy of the environment and are the most exposed to environmental stresses. Stress is the trigger that “switches on” phytochemical production in a plant. Without at least a little stress, plants will just continue to grow more leaves and roots, and will not reallocate their limited resources towards accumulation of internal phytochemicals. Because they are so rich in health-protective compounds, I like to say that wild plants are “stressed for success."
Do cultivated plants have the same properties?
While cultivated plants also produce phytochemicals, modern agricultural breeding and cropping has tended to select in favor of certain plant traits, for example, sweeter, starchier, plumper or rounder fruits. Simultaneously, it has selected against some of the health-protective, complex phytochemical mixtures that exist in wild plants. Plants in orchards or carefully-tended fields tend to be protected by the farmer from natural stressors like insects or competitive weeds. Cultivated plants are usually provided with the best soil fertility and irrigation, so that none of those factors could create stress or inhibit productivity.
Cultivated fruits and vegetables are also important and underappreciated resources for health; they provide excellent nutritive and phytochemical benefits, and we all can benefit from increased use of all fruits and vegetables in our daily diet. The only difference is that wild fruits, while they may not be as high-yielding or taste as sweet as some cultivated fruits, tend to be a more concentrated, phytochemically-dense, potent resource for health-protective phytochemicals.
How can I maximize the effects of these phytochemicals?
Phytochemicals in plant foods almost never work solo. Plants contain a diverse and typically redundant complement of phytochemicals. Interactions between these phytochemicals, all eaten together in the food, can greatly increase the potency for human health maintenance. When many different healthy foods are included in a daily diet, the defensive shield against chronic diseases becomes all the more formidable.
Which wild berries should I incorporate into my diet?
Not everyone can pick wild berries or has access to other wild edible plants. And more importantly, not everyone knows which plants in the wild are safe to eat! But everyone can still capitalize on the benefits from natural phytochemicals by selecting plant foods from your supermarket or farmer’s market that are harvested in the wild, or are naturally grown with minimal inputs so that the plants benefit from natural environmental stresses while they grow and develop.
Try the following three fruits, all of which pack a powerful punch of phytochemicals along with excellent taste:
Wild blueberries are one of only three berry fruits that are native to North America – it is a true all-American fruit. The intensely pigmented wild blueberries are actually a commercial crop, grown in the state of Maine and in maritime provinces of eastern Canada, like Nova Scotia, Prince Edwards Island and New Brunswick. These wild blueberries are tended in open fields with only moderate grower inputs, and they are not deliberately planted; they have naturally colonized their fields.
Wild blueberries have superb antioxidant capacity, and have demonstrated a remarkable ability to lower blood glucose levels for diabetics. A diet including wild blueberries has been linked to improved motor skills, and reverses the short-term memory loss associated with the human aging process.
As a cancer-fighting wild fruit, the interactions between natural phytochemicals in these densely packed little berries have been shown to inhibit each stage of the carcinogenesis process – the initiation, promotion and progression stages – delivering true multifaceted protection. The berries are smaller than cultivated varieties, and can only be found in the frozen foods section of the supermarket. Since they are sorted, cleaned, and frozen immediately after harvest, they can easily be poured out of the bag and used anytime. Pour a half-cup into a bowl and cover it with steaming hot oatmeal for breakfast every morning – it takes only minutes and provides a satisfying phytochemical punch of protection that lasts all day long.
Black currants are an astringent, pigment-rich edible berry that has historically been more popular in Europe and Australasia than in America, but increasing research on its multiple health benefits make it an excellent fruit to incorporate into the overall dietary mix. The berry’s ability to modulate oxidative stress and inflammation in humans not only enhances the body’s natural immune defenses against diseases including cancer, but eating this fruit helps to minimize muscle damage from sustained sports training (sports recovery), and reduce inflammation associated with allergy-induced asthma.
Black currants are available frozen or incorporated into juices, preserves and other products. The flavonoid group of phytochemicals (anthocyanin pigments, epigallocatechins and proanthocyanidins) appears to be collectively responsible for these health-enhancing attributes.
Muscadine grapes are a hardy native American grape that is grown mostly in the southeastern states of the USA. Its naturally high inherent concentrations of flavonoids (resveratrol, quercetin and ellagic acid) make these grapes naturally resistant to many of the diseases that plague other types of grapes – and these same compounds are what make muscadine grapes so protective against many different types of human cancers. Cherokee and Creek Indians historically used muscadine fruits in traditional recipes and for medicinal use. Today, muscadine juices and wines are widely available, but the grapes are also processed into preserves, salsas and frozen products.
These and other cancer-fighting fruits can easily be incorporated into meals and snacks throughout the week. The best strategy is to eat the whole fruit so that you can benefit from the health-protective phytochemicals in the flesh, skins, juice and seeds all at once.
For example, throw in a handful of berries to make a green salad not only healthier, but more colorful and appetizing. Click here to get the recipe for a rainbow superfood salad with blueberries and balsamic. Click here to get the recipe for a carrot salad with wild blueberries.
Berries and grapes both mix well with other fruits as a simple dessert, or can be blended into smoothies which can be as versatile as you want – just try different fruit and vegetable combinations. Click here to get the recipe for a wild blueberry and avocado smoothie.
Try a superb zesty salsa recipe which substitutes wild blueberries in place of the usual tomatoes – it is an incredibly delicious way to eat these berries year round. Click here for a wild blueberry salsa recipe.
Be proactive about fighting cancer with your own diet. Mix and match a variety of colorful fruits and vegetables on the menu each week, and keep an eye out for the wild ones – their rugged survival strategies translate into the most versatile and health beneficial phytochemicals for you.